The purpose of the proposed research is to advance the science of violence prevention by conducting a rigorous study of the impact of Early Head Start (EHS) on child abuse and neglect. EHS is a primary prevention program for low-income infants, toddlers, and their families. Although EHS has been shown to positively impact risk and protective factors associated with maltreatment, its effectiveness in preventing abuse and neglect has not been well-studied. The proposed project addresses critical gaps in maltreatment prevention science by: (a) using a randomized experimental design; (b) following a large study sample longitudinally (birth to age 15) to assess long-term prevention outcomes; (c) utilizing documented reports of maltreatment as a measure program effectiveness; (d) identifying key short term program mediators of later maltreatment; and (e) differentiating program impacts for different types of abuse (neglect, physical abuse, and sexual abuse). The considerable public health impact, societal costs, and detrimental short and long-term health consequences of child abuse and neglect are well documented, and the identification of effective maltreatment prevention programs is a priority area for the CDC. As one of the largest programs serving at-risk infants and toddlers in the country, results from this study have significant potential for policy impact by providing evidence that the EHS program can reduce dangerous and costly child maltreatment. Today, EHS serves only 5% of eligible children; further support for its effectiveness will lend weight to expansion and advocacy efforts that could significantly reduce the number of children maltreated in this country. Further, the very young children served by EHS are most vulnerable to injury and death related to maltreatment, and thus most in need of effective evidence based prevention services. The present study will address five research questions: (1) Is EHS effective in reducing child maltreatment among participating children and families? (2) Do the positive impacts of EHS on early child and parent outcomes mediate later program effects on child maltreatment? (3) Is EHS more effective in preventing maltreatment for specific subgroups of children or families? (4) What characteristics of EHS programs are associated with better prevention outcomes? (5) How do children in EHS and the control group differ with regard to the timing, type, severity and/or chronicity of maltreatment experienced? This study will use methodology tested in a recent pilot study to obtain child welfare records for 3001 children and their caregivers in 17 EHS programs who participated in a national randomized clinical trial of program impacts starting in 1996. The study will link maltreatment data with the extensive outcome data collected in the national EHS study (interviews, observations, and direct child assessments when children were 14, 24, 36, and 60 months old). Qualitative data from child welfare case files will allow the study to address methodological issues that have hampered prior research on the prevention of child abuse and neglect.